Oil spill reclamation system

ABSTRACT

An oil spill reclamation system utilizes an elastomeric foam functionalized to exhibit both oleophilic and hydrophobic properties. The foam material is contained in permeable pods connected to each other in a chain to form a boom strung in a closed loop around the oil spill. As each pod is brought into contact with the spilled oil, the foam material absorbs it to saturation. The pods are linked through an inflated flexible hose that ensures their buoyancy. The chain of pods is continuously processed in one or more barges that include equipment to press the absorbed oil out of each pod and a conveyor system for retrieving the pods from the water, pulling them through the press, and returning them to the water in a continuous cycle of operation. Positioning buoys with vertical rollers are used to retain the general shape of the containment loop defined by the continuous boom.

RELATED APPLICATIONS

This patent application is based on and claims the priority of U.S.Provisional Application Ser. No. 61/361,974, filed Jul. 7, 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is related in general to systems for clean-up andrecovery of oil spills. In particular, the invention pertains to asystem based on the use of an elastomeric oleophilic/hydrophobic foammaterial suitable for continuous on-site oil extraction and separation.

2. Description of the Related Art

Since the early times of off-shore drilling, concerns over oil spillshave created much debate and tension between environmental andproduction interests. The potential economic damaged resulting fromlarge spills has spurred much research, but no solution has proven to besatisfactorily effective in protecting wildlife and shore lines frommajor spills. As evidenced by the Exxon Valdez tanker rupture and therecent well blow-out in the Gulf of Mexico, serious periodic accidentsare almost unavoidable and the consequences can be disastrous.

Typically, oil spills are addressed first by containment efforts andthen by some method of oil collection and remediation. Absorbentfloating booms, in-situ bio-remediation, dispersing detergents andcontrolled fires are all examples of various approaches used to date tocontrol the damage of oil spills. No mobile, continuous process existsfor containing an oil spill and at the same time extracting andrecovering the oil from the water. The present invention addresses thisproblem with an effective and highly efficient solution.

BRIEF SUMMARY OF THE INVENTION

The invention is based on the use of an elastomeric foam that has beenfunctionalized to exhibit both oleophilic and hydrophobic properties.Because of its foam structure, this material can be used to entrap oilthat can then be pressed out and recovered on account of the material'selastomeric characteristic. The separation of oil from water is enhancedby the hydrophobic property of the foam, while the absorption of oil isgreatly enhanced by its concurrent oleophilic characteristics.

The foam material is contained in permeable pods connected to each otherin a chain to form a long boom strung in a closed loop around the oilspill, or a portion thereof, for containment and processing. As each podis brought into contact with the spilled oil, the foam material in thepod absorbs it to saturation, thereby extracting it and separating itfrom the surrounding water. According to one aspect of the invention,the pods are connected to one another through linked sections of aninflated flexible hose that ensures their buoyancy as well as that ofthe entire boom. Therefore, the pods and the linking hose componentsprovide a barrier at the surface that contains the spill within theclosed loop.

According to another aspect of the invention, the chain of pods iscontinuously processed in one or more barges that include equipment topress the absorbed oil out of each pod and a conveyor system forretrieving the pods from the water, pulling them through the press, andreturning them to the water in a continuous cycle of operation.Positioning buoys with vertical rollers around which the chain of podscan travel are used to retain the general shape of the containment loopdefined by the continuous boom.

Several schemes of containment and recovery are considered, some withstationary barges and some subject to tug-boat traction. The latterschemes provide the additional advantage of accumulating the floatingoil at the trailing end of the loop where it is continuously recoveredat higher density by the moving chain of pods as the processing barge,pulled by the tug boat, proceeds through the water.

Various other purposes and advantages of the invention will become clearfrom its description in the specification that follows and from thenovel features particularly pointed out in the appended claims.Therefore, the invention consists of the features hereinafterillustrated in the drawings, fully described in the detailed descriptionof the preferred embodiments and particularly pointed out in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a pod made of flexible nettingmaterial for housing the elastomeric oleophilic/hydrophobic foam used topractice the invention.

FIG. 2 is another illustration of the pod of FIG. 1 showing the foammaterial contained in it and the tubing sections supporting and linkingthe pods in a chain to form a floating boom.

FIG. 3 is an illustrative, schematic, plan view of the type ofcontainment boom achieved by connecting the pods of the invention in acontinuous chain with a supporting floating hose of the type shown inFIG. 2.

FIG. 4 illustrates the connection of the pods of the invention though aninflatable hose or tube to form a chain-like boom for containing an oilspill and for recovering the oil it in a continuous cycle of absorptionby contact in the water, mechanical separation on a barge, and return tothe water for renewed absorption.

FIG. 5 illustrates schematically an intake ramp for conveying the boomto the top of a barge for processing according to the invention.

FIG. 6 illustrates schematically a pressing facility for the mechanicalseparation of recovered oil from the pods of the invention in acontinuous cycle of operation.

FIG. 7 is a top plan view of a buoy suitable for positioning the boom ofthe invention in a loop encircling an oil spill being reclaimedaccording to the invention.

FIG. 8 is a schematic cut-out side elevational view of the buoy of FIG.7.

FIG. 9 illustrates a system where two very long booms are circulatedfrom a barge pulled by a single tug boat and attached to a collectionbarge to which the recovered oil is pumped for larger scale storage.

FIG. 10 is an illustrative, schematic, plan view of anotherconfiguration of containment booms operating as continuous chains from asingle reclamation barge connected to a trailing collection barge andpulled by two tug boats.

FIG. 11 is an illustrative, schematic, plan view of a configuration ofcontainment booms operating as continuous chains from two reclamationbarges sharing one of the booms, where each barge is pulled by a tugboat.

FIG. 12 is an illustrative, schematic, plan view of a large scaleconfiguration of containment booms operating as continuous chains fromfour reclamation barges sharing one of the booms.

FIG. 13 is an illustrative, schematic, plan view of an even larger scaleconfiguration of containment booms operating as continuous chains from amultitude of reclamation barges in conjunction with a stationarycontainment barrier protecting a shore line.

FIG. 14 is a side elevational view of a processing operation on areclamation barge where three presses operating in sequence are used toprogressively remove first water and then recovered oil from the foammaterial contained in the pods of the invention.

FIG. 15 is a top plan view of the presses of FIG. 14.

FIG. 16 is a cross-section of a pod fitted with longitudinal fins toproduce rotation of the pod as it travels through a body of water.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The invention relies on the use of a foam material that exhibitsconcurrent oleophilic and hydrophobic properties that allows it toabsorb oil while repelling water, a critical condition for the highefficiency of the process of the invention. In addition, the material isboth elastomeric and structured as a foam, the combination of whichenables the absorption of relatively high volumes of oil per volume offoam (due to the typically large proportion of voids in the foam) andthe subsequent mechanical recovery of the oil from the foam simply bysqueezing it out of the foam. These properties together make it possibleto carry out the process of the invention with speed and efficiency.

The surface functionalization of materials to render them oleophilic bythe deposition of appropriate moieties (such as alkyl acrylates,methacrylate, and vinyl compounds of polyesters, polyurethanes,polyepoxides, bisphenol A resins, and phenoxy resins, for example) iscommonly practiced in the art of surface functionalization. Thehydrophobicity of materials by the addition of non-polar hydrophobicmoieties (such as silicone and fluorocarbons) is similarly wellunderstood. See, for instance, Hao Yang, Pihui Pi, Zhi-Qi Cai, XiufangWen, Xibo Wang, Jiang Cheng and Zhuo-ru Yang, “Facile preparation ofsuper-hydrophobic and super-oleophilic silica film on stainless steelmesh via sol-gel process,” Applied Surface Science Volume 256, Issue 13,15 Apr. 2010, Pages 4095-4102. One elastomeric foam exhibiting suchcombination of oleophilicity and hydrophobicity is the foam currentlysold by Tri-State Biopolymers, LLC, of Lake Forest, Calif., under thetrademark VOFOAM™.

The term “absorption” is commonly intended to mean a process ofdiffusion of a substance into another without chemical or physicalbonding, while the term “adsorption” is commonly intended to mean theadhesion of a chemical species onto the surface of particles withoutcovalent bonding but through the action of physical attractivephenomena, such as van der Waals forces. Inasmuch as the oleophilicityexhibited by the foam of the invention is a combination of both, theseterms are used interchangeably herein for simplicity unless thedistinction is relevant to the description. The terms “elastomer” and“elastomeric” refer to polymers with the property of viscoelasticity(colloquially “elasticity”), generally having notably low Young'smodulus and high yield strain compared with other materials.

Referring to the drawings, wherein like parts are labeled with likenumerals or symbols, FIG. 1 is a schematic diagram of a pod 10 suitablefor practicing the invention. The pod 10 is preferably an elongated,substantially cylindrical container made of permeable flexible material,preferably netting 12, through which oil can penetrate rapidly andwithout obstruction. As shown in FIG. 2, the pod 10 is filled withchunks 14, preferably spherical in shape for volumetric efficiency, ofelastomeric foam having substantial oleophilic and hydrophobicproperties, as described above.

As illustrated in FIG. 3, many pods 10 are connected together in a longchain to form a floating boom 16 that is placed around an oil spill 18in a water body (or a portion thereof) in order to contain the oil andprevent its dispersion over a larger area of the body of water. In thepreferred embodiment of the invention, each pod 10 is attached to asection 20 of flexible hose or tube threaded though the pod, as shown inthe figures (see FIG. 2), and the various hose segments are connected toone another through air-tight quick-disconnect couplers 22, so that along boom of regularly spaced pods can easily and rapidly beconstructed. As shown in FIG. 4, each coupler 22 is equipped with acheck valve 24 to inflate the long hose produced by the coupled sections20 so as to provide the necessary buoyancy for maximum efficiency of theboom 16 in containing and recovering the oil. A zipper 26 or othersimilar containment means or enclosure may be used to enclose andprovide access to the interior of each pod 10.

According to the invention, a closed-loop chain of pods so constructedis used both as a containment boom and as a conveyor for continuouslyabsorbing and releasing the oil contained by the boom. A barge with apress for squeezing the oil out of the pods is provided on site and thepods are continuously fed through the press and released back into thewater, thereby creating a continuous cycle of operation. Referring backto FIG. 3, two booms 16 and 16′ are shown operating in parallel with asingle processing barge 30, each advancing in the direction indicated byrespective arrows A and A′. To effect such movement of the booms, thebarge 30 is equipped with respective intake ramps 32, illustratedschematically in FIG. 5 (also showing the front of the barge inelevational view), where a belt conveyor 34 engages the couplers 22between the pods of the boom and pulls each pod up onto the barge. Theupper end of the intake ramp 32 is pivotally mounted on the back side 36of the barge 30 and is supported at the lower end by a floatingstructure 38 that includes floating rollers 40 that funnel the pods 10toward the conveyor 34 for engagement by the belt. A shock absorbingcylinder 40 is used to reduce the effect of water elevation changesproduced by waves or turbulence. Power cleats (not shown) and aV-grooved belt can be used in the conveyor 32 to grab each coupler 22between pods to advance the booms 16,16′ through the barge 30 forprocessing of the pods.

As also shown in FIG. 6, the pods 10 of each boom 16,16′ are furtheradvanced on the barge 30 by a similar conveyor 42 that advances the boomthrough at least one press 44, where each pod 10 is squeezed tomechanically remove the oil from the foam 14. Such a press 44 includes apiston 46 that is operated to push downward as each pod is moved throughthe press by the conveyor 42. A top belt 48, moving on rollers in thesame direction and at the same speed of the conveyor 42, is providedunder the surface of the piston 46 and is adapted to squeeze the podswithout stopping the conveyor and without producing damaging deformationto their structure other than vertical compression and relatedmechanical extraction of the oil from the foam 14. The motions of theconveyor 42, belt 48 and press 44 are synchronized to ensure as smoothas possible a passage of the pods through the press. The oil released bythe process is collected in a storage reservoir in the barge (not shown)through a collection chute 50 under the press 44 for later transport toa tanker or other larger storage facility. The processed pods are thenreturned to the water, in a continuous cycle of operation, through asimilar return ramp 52 at the other end or the side of the barge 30 (seeFIG. 3). As the booms 16,16′ circulate as illustrated, each pod 10 isagain placed in contact with oil in the water, if any, where it isabsorbed, the pod is circulated and pulled back onto the barge 30 andpressed out for recovery in a continuous cycle of operation.

In the embodiment of the invention illustrated in FIG. 3, the barge 30is intended to be pulled by a tug boat 54 during operation of therecovery system. Each of the booms 16,16′ is constrained by a buoy 56attached to the front of the barge 30 by a cable 58 that defines, incombination with the relative rigidity of the boom, the shape of thefront side of the loops formed by the booms 16,16′ in the water. FIGS. 7and 8 illustrate in schematic top plan and side elevational views thepreferred configuration of the buoy 56. Referring to FIG. 7, two pairsof rolling tanks 60 are mounted vertically on a support structure 62spaced apart a distance adequate for the pods 10 of the booms of theinvention to pass through. The normally empty tanks provide buoyancy forthe entire structure and serve as vertical rollers to constrain andfacilitate passage of the pods as the boom is circulated through therecovery circuit of the invention. As seen in FIG. 8 (with one half ofthe structure 62 removed), an additional float 64 is provided under thestructure 62 for buoyancy and a remotely controlled rudder 66facilitates the process of positioning the buoy 56 with respect to thebarge 30. In addition, each rolling tank 60 is equipped with valves (notshown) that make it possible to fill the tank with water to differentdegrees to reduce the buoyancy of the assembly and thus lower the buoy(and therefore also the boom) if necessary to improve the recovery ofoil under the surface of the water.

Another buoy 56 at the trailing edge of each boom similarly constrainsthe trailing edge of the boom in the water (see FIG. 3). A retractablecable 68 attached to a structure connecting the two buoys 56 may be usedto lengthen or shorten the portion of boom directly behind the barge,thereby changing the shape of the loops formed by the booms in thewater. Those skilled in the art will recognize that such shape will varywith the rigidity of the hose 20 supporting the pods, the distance ofthe trailing buoys 56 from the barge, the length of the cables 58, theposition of the rudders 66 in each buoy, and the speed of the entiresystem provided by the tug boat 54.

Thus, an oil recovery system has been shown where a closed-loop boom ofuniformly spaced pods containing elastomeric oleophilic/hydrophobic foammaterial is circulated continuously around a predetermined surfacesection of contaminated water to sequentially absorb oil and release itby pressing it out of the foam in a process carried out on a barge, andthe pods are then returned to the water in an expanded condition torepeat the cycle of recovery. Controllable buoys are tied to the boom todefine its shape and position and, if necessary, to change the exactdepth of the boom skimming operation along the surface of the body ofwater. As illustrated in FIG. 3, more than one containment and recoveryloops can be operated at the same time from a single barge. The systemmay be run with a stationary barge or in motion, where the barge ispulled by a tug boat while the boom or booms circulate around the loopdefined by each.

As one may well imagine, many different schemes of operation arepossible by utilizing different numbers of pods, booms and barges aloneor in combination with other kinds of equipment, primarily tankers tostore large quantities of oil recovered from the barges. For example,FIG. 9 illustrates a system where two very long booms 70,70′ (shown openended large but in fact enclosed to define continuous loops) arecirculated from a barge 30 pulled by a tug boat 54 and attached to acollection barge 72 to which the recovered oil is pumped for largerscale storage. The barge 72 may be replaced by an empty one as neededwithout interruption of operations. A barrier 74 of floating pods orother protective material can be used on each side of the barge 30 toprevent the oil from escaping through the intake and return ramps 32 and52.

Another scheme of operation is illustrated in FIG. 10, where two tugboats 54 are used to pull a barge 30 operating in the same configurationof FIG. 3 but also towing a collection barge 72. FIG. 11 illustrates ascheme where a larger boom loop 76 is shared between two barges 30 towedconcurrently by respective tug boats 54. In both configurations the restof the equipment is utilized as described.

FIG. 12 illustrates a large scale configuration wherein four barges 30operate in stationary manner sharing a very large inner boom loop 78concurrently with respective outer boom loops 80. The figure shows threecollection barges 72 attached to respective recovery barges 30 and otherservice vessels 82 in transit within the area of reclamation. FIG. 13illustrates a case where a barrier 84 has been placed in front of acoast line L to prevent spilled oil from reaching it while the recoverysystem of the invention is operating in various configurations on theother side of the barrier 84.

While the invention may be practiced effectively as described, it hasbeen demonstrated that a more efficient recovery approach requires thatthe oil be recovered from the pods 10 in two, preferably three pressstages. As shown in elevational and top views in FIGS. 14 and 15,respectively, an optimal way of separating the oil from the foam 12 inthe pods 10 of the invention is to first compress the pods to about 90percent of their saturated volume in a first press 86. This first stepremove essentially all water that necessarily remains entrapped by thepods in spite of the foam's hydrophobicity. This oily water ispreferably treated on the barge, such as in hydrocyclones or centrifuges(not shown), to recover the oil and return the water off the barge. Thepods 10 are then pressed to full compression in a second press unit 88,where essentially water-free oil is completely squeezed out of the pod.If a more gradual compression of the pods is desired without affectingthe overall speed of oil recovery, a third press 90 may be added to theoperation, each extracting a fraction of the oil carried by the pods.

Because the bottom part of each pod 10 is exposed more directly to oilthan the top part of the pod, the oil is absorbed more rapidly at thebottom and the top portion tends to become saturated more slowly bydiffusion and oleophilic attraction. Therefore, depending on conditions,the pods may not be completely saturated prior to being conveyed to thebarge for the recovery the oil. In order to ameliorate this condition,as illustrated in cross-section in FIG. 16, an embodiment of a pod 10 ofthe invention may include longitudinal fins 92 that cause the pod torotate as it is being dragged through water, thereby improving theexposure of all parts of the pod to the oil on the surface of the water.

While the invention has been shown and described herein in what isbelieved to be the most practical and preferred embodiments, it isrecognized that departures can be made therefrom within the scope of theinvention. For example, optimization studies currently in effect haveshows that the removal of oil from the pods may be improved by havingthe two conveyors 42 and 48 operating in the presses 44, 86, 88 and 90(or in selected ones of them) disposed at a converging angle, ratherthan in the parallel position shown in FIG. 6.

It is also understood that a single large pod could be used incombination with a processing vessel to recover oil from a relativelysmall area affected by an oil spill. Such a pod could be exposed to theoil and processed through a continuously moving boom, as described, orin batch fashion, by dipping it in the oil spill and retrieving it forprocessing as needed. Therefore, the invention is not to be limited tothe details disclosed herein but is to be accorded the full scope of theclaims so as to embrace any and all equivalent processes and products.

1. A continuous oil recovery system comprising: a boom including aplurality of pods containing an elastomeric hydrophobic/oleophilic foam;a conveyor system adapted to continuously move said boom from a body ofwater onto a vessel at a predetermined speed; and oil recovery equipmenton said vessel, said recovery equipment being adapted to press the foamto extract fluids contained therein.
 2. The system of claim 1, whereinsaid conveyor system includes intake and return ramps connected to thevessel and a vessel conveyor advancing the boom through the vessel. 3.The system of claim 2, wherein said recovery equipment includes a presswith a piston adapted to compress the foam.
 4. The system of claim 3,wherein said piston includes a conveyor facing the boom advancing at aspeed equal to said predetermined speed of the boom.
 5. The system ofclaim 1, wherein said recovery equipment includes a press with a pistonadapted to compress the foam.
 6. The system of claim 1, wherein saidrecovery equipment includes a plurality of presses operating in seriesand adapted to progressively squeeze said foam.
 7. The system of claim1, wherein said conveyor system includes buoys coupled to the boom. 8.The system of claim 7, wherein each of said buoys includes a rudder. 9.The system of claim 7, wherein each of said buoys includes a tank withvalves for varying a level of liquid contained in the tank.
 10. Thesystem of claim 1, wherein said boom includes inflatable components. 11.The system of claim 1, further comprising at least one tug boat pullingthe vessel.
 12. An oil recovery system comprising: a boom including apod containing an elastomeric hydrophobic/oleophilic foam; a retrievalsystem adapted to move said boom from a body of water onto a vessel; andoil recovery equipment on said vessel, said recovery equipment beingadapted to press the foam to extract fluids contained therein.
 13. Amethod of recovering oil from a body of water, said method comprisingthe following steps: placing in the water a boom including a pluralityof pods containing an elastomeric hydrophobic/oleophilic foam;continuously moving said boom from the body of water onto a vessel at apredetermined speed; and pressing the foam to extract fluids containedtherein.
 14. The method of claim 13, wherein said pressing step iscarried out on the vessel with a press having a piston adapted tocompress the foam.
 15. The method of claim 14, wherein said pistonincludes a conveyor facing the boom advancing at a speed equal to saidpredetermined speed of the boom.
 16. The method of claim 13, whereinsaid pressing step is carried out on the vessel with a plurality ofpresses operating in series and adapted to progressively squeeze saidfoam.
 17. The method of claim 13, wherein said step of continuouslymoving said boom from the body of water onto the vessel includes passingthe boom through a plurality of buoys coupled to the boom in the water.18. The method of claim 17, wherein each of said buoys includes arudder.
 19. The method of claim 17, wherein each of said buoys includesa tank with valves for varying a level of liquid contained in the tank.20. The method of claim 13, wherein said boom includes inflatablecomponents.